Chuck D. Bones
Circuit Wizard
The question we should be asking is "Why do we need to add a buffer to cure squealing?" Squealing is just the symptom, not the root cause of the problem.
Very confined PCB with Input & Power traces close together combined with High Gain would be a possible cause!The question we should be asking is "Why do we need to add a buffer to cure squealing?" Squealing is just the symptom, not the root cause of the problem.
I suspect that it's a routing issue. The layout is more compact than it probably should be on account of the tube socket mounting setup, so the routing probably isn't following best practice for high gain design.The question we should be asking is "Why do we need to add a buffer to cure squealing?" Squealing is just the symptom, not the root cause of the problem.
I've stayed out of this one for a while and privately told certain individuals what I think but ultimately, you and I are in agreement that putting a buffer in front of it is like putting a painting over a hole in the wall. You don't see the hole anymore but it is very much still there.The question we should be asking is "Why do we need to add a buffer to cure squealing?" Squealing is just the symptom, not the root cause of the problem.
British born, but I generally see them considered to be an Aussie band by other people. They did spend their main formative years in AustraliaThe Brothers Gibb were all from England, grew up in Australia!!!
It was less noisy, but it also dropped the gain a bunch. I think I may have messed up somewhere in my vero layout. I'll have more time to work tonight than I did last night, I'll see if I can figure it out and try again.So how did that different buffer workout? less noisy?
Have you considered offloading the boost converter to a daughterboard that mounts through header pins to the main board? You could likely fit something along the input side or output side wall of the enclosure (the output side is probably a slightly better choice). The additional room on the main board may allow for more effective routing.I suspect that it's a routing issue. The layout is more compact than it probably should be on account of the tube socket mounting setup, so the routing probably isn't following best practice for high gain design.
I haven't really considered it. The goal of the whole project was to make it easy to assemble, once I open the door to daughter boards it completely changes things. The easiest way would be to put the tubes on daughter boards and mount the PCB horizontally, which is what I do for my usual builds and it gives me a lot more room to work with.Have you considered offloading the boost converter to a daughterboard that mounts through header pins to the main board? You could likely fit something along the input side or output side wall of the enclosure (the output side is probably a slightly better choice). The additional room on the main board may allow for more effective routing.
Next you’ll be claiming Dragon, Crowded House, and Split Enz!British born, but I generally see them considered to be an Aussie band by other people. They did spend their main formative years in Australia
@tcpoint, how much gain do you get with the 12AU7s in the BE? Can you get it "clean"? I'm doing that with my Space Heater and a 12AU7 but I'm wishing for some basic EQ, would be cool to be able to do it with the BE.Quick note. I put 12au7 tubes in. No squeal. I'm going to probably try a combo of 12au7 and 12ax7/12at7. I like the 12au7s but I need a little more gain. I didn't need a buffer, either. I really like the 12au7s but would like to have 12ax7 build and 12au7 build. Different pedals but both really good.
I had been experimenting with a buffer on vero and it seems like that does the trick. I ordered new footswitch PCBs with a built-in buffer that just shipped from China today, so I should see them next week. Once I have the chance to verify that they're going to work the way I want I'll let everyone know and start getting them out to people.I may have missed it, but what’s the status of the board and the squealing? Is the solution an integrated buffer on the switching daughterboard, or are there plans to revise the board to address the issue?